


Phantom Occult

by CielPansyhive



Category: Kuroshitsuji | Black Butler
Genre: Alternate Universe - Modern Setting, Amnesia, Apocalypse, Blood, Dark, Death, Demons, Eventual Smut, Flashbacks, Ghosts, Gore, Grim Reapers, Hell, M/M, Magic, Phantomhive Twins - Freeform, Psychic Abilities, Psychics, SebaCiel - Freeform, Sickle Cell Disease, Supernatural - Freeform, Undead, Visions, Witches, Zombies, half demon sebastian, sickle cell anemia, spells, will add more tags later
Language: English
Status: In-Progress
Published: 2018-06-12
Updated: 2018-06-12
Packaged: 2019-05-21 14:01:13
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Major Character Death, Rape/Non-Con
Chapters: 1
Words: 4,402
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14916690
Author URL: https://archiveofourown.org/users/CielPansyhive/pseuds/CielPansyhive
Summary: “Saving people, hunting things...family business!” The Phantomhives have been on the road most of their lives, taking out all the nasties that go bump in the night. Vincent and his twin sons have teamed up with a half demon named Sebastian and a witch, Sieglinde. Sebastian has very little memory of his past. He was found by Vincent and Cedric (Undertaker) on one of their hunts. In search of answers, Sebastian is trying to track down his demonic father. Sebastian has proven his loyalty to the Phantomhives time and time again. He will, as Vincent’s last request, ‘look after his boys.’ Following in their father and grandfather’s footsteps the twins take on cases involving the supernatural. Vincent Jr. has his work cut out for him with Ciel’s fragile health (Sickle-Cell Disease/Anemia) and Sebastian’s ever changing and out of control abilities. They may need to seek out a higher being to help them and save the world from damnation.





	Phantom Occult

**Author's Note:**

> Thank you for reading! This is a supernatural au with the the Phantomhive twins. Our!Ciel is still named Ciel while Real!Ciel is named Vincent Jr. (goes by Vince) This is Sebaciel (Seb/Our!Ciel)   
> Check out my tumblr: https://cielpansyhive.tumblr.com/  
> Please leave me some kudos if you enjoy this!

It was suppose to be a simple hunt. A few recently deceased citizens got up and lumbered out of the morgue, shortly after there were reports of a ‘rabies outbreak.’ The Phantomhives and Sebastian knew better, the undead were taking over. Vincent and Sebastian left for the small town. The twins stayed back at a hotel a few states over just to be safe. They were only going to be gone a couple days. That is before they arrived to the chaos unfolding in the town. In the time it took for them to get there the total number of the undead had tripled. The undead wandered about in the open, searching for food. Cars were crashed into obstacles and engulfed in flames. Buildings were trashed, windows broken. They drove around, looking for any signs of life. They found the remaining citizens boarded up in a large church. They were scared and confused, families were shattered, and they were uncertain of their own fate. The plan had changed, now it was a rescue mission. Vincent ordered Sebastian to get as many citizens as possible to safety while he distracted the undead. For some reason supernatural beings were always drawn to Vincent, like he was some sort of beacon. Sebastian hated the plan, the odds weren’t in Vincent’s favor, but he had witnessed the man do a lot of things he thought were impossible. Sebastian safely relocated the remaining citizens to the next town over, while it was not ideal at least they were at a safer distance. They phoned in fellow hunters, with better weapons. They would set up a controlled blast to the infected town destroying everything in the area within four hours. It was enough time for Sebastian to get Vincent and start their drive back to the twins. When Sebastian arrived at the church he saw blood had been splattered everywhere, it was a massacre. Standing in the middle of decapitated corpses was Vincent. He was covered in gore, breathing hard and clutching his side. When they locked eyes Vincent tried to smile, the citizens were safe, but it came out a grimace.

“Vincent?” Sebastian ran towards him just as he collapsed. “Vincent!” he held him in his lap, concern covering his face. Vincent lifted a shaking hand. He had a fist sized hole in his side. He quickly placed his hand back over the wound. It was the only thing keeping his innards from falling out.

“I guess it really was a stupid plan,” he tried to laugh but came out choked. “You did well, you-you saved them.” Sebastian’s eyes started to water.

“No, if it wasn’t for you they never would have made it. I took too long…I-I should have got back to you faster. Maybe if I did you wouldn’t be…”

“Sebastian, you’re not going to cry over me now are you?” he smirked. “What kind of demon are you?” he tried to mask his pain, but he knew Sebastian saw through it.

“Obviously not a very good one,” he sobbed. “Just hang in there, we’ll see Sullivan. She can fix…”

“No,” he sighed. “It’s too late…for me Sebastian. I’m wounded and I have no doubt when I pass…I’ll end up like the others,” he winced as he moved his hand and took off his sapphire ring, the same ring that was handed to him when his own father passed away, and placed it in Sebastian’s palm. “Bring…t-this back…to them.” Sebastian nodded. Vincent’s shaking was getting worse; his skin was pale and clammy. Bloodied coughs wracked his body.

“I’m so sorry,” Sebastian kissed his forehead. Vincent was the closest he had to a father. He took him in and raised him despite his demonic genes. He easily could have killed him. He owed Vincent his very life, yet there was nothing he could do to spare him his. He watched Vincent’s blue eyes become clouded, almost grey and lifeless.

“Listen,” he wheezed. “You’re… all they have…now. You look after my boys, okay?” Sebastian nodded. “Promise me,” he weakly grasped at Sebastian’s shirt. “Protect t-th-them.”

“I promise, I promise,” he let his tears fall. He knew Vincent’s time was almost up. He placed his taloned hand on Vincent’s head. Vincent closed his eyes and nodded. “I’m sorry Vincent.” He looked away as he crushed in Vincent’s skull. He retched when he heard the sickening crack of bone and felt the mush of brain matter. After 13 years of hunting he never thought he’d have to make good on his promise. It was something he always said, ‘don’t let me turn,’ whether they dealt with zombies, vampires, werewolves, whatever monster. Sebastian stood up, holding tightly onto the ring, and walked to the car. Once in the black SUV his resolve crumbled. His cries were closer to screams of anguish, so loud they threatened to shatter glass. When Vincent died it was like a part of him died too. He almost thought he felt the pain in his side that Vincent must have felt. He was hit with another wave of nausea. He took a deep breath and slowly exhaled, trying to calm himself.  He tucked the ring into his breast pocket. It felt as heavy as his heart now. He was sinking, drowning, when he thought of Vincent’s sons. “How do I tell them? How do I tell the boys?” he sobbed. He started the car. As much as he felt he needed more time to pull himself together he knew he needed to get back to the twins. “Ciel needs me, now more than ever.”

*

“What’s taking them so long?” Vincent Jr. grumbled. He was pacing on the ugly floral carpet of their hotel room. “It was a simple mission, if we were there it would have already been taken care of!” he slammed a fist on the end table. “Aim for the head, it’s not that hard!”

“Ugh, Vince, too loud,” Ciel complained. He was bundled up in the bed, blankets up to his nose, though he still was shivering. The room was slightly chilly, but with Ciel’s condition and low body weight it was torturously cold.

“I’m sorry,” he signed. “I just get nervous,” he sat down on the bed and smiled sympathetically. “Are you feeling any better?”  

“No,” Ciel mumbled. He was slightly pale and had a look of sheer exhaustion. “My headache isn’t going away and everything hurts.”

“When they get back we’ll see Sullivan,” he moved Ciel’s hair out of his face. “We’ll get you some more pain medication. Why didn’t you tell any of us you were running so low?”

“I didn’t want to be a bother,” he huffed. “I have a lot of Ibuprofen still.”

“Yeah and that helps so much,” he rolled his eyes.

“I’m sorry Vince,” he started crying. “I’m such a burden on all of you. You could have gone with them and instead you’re stuck here babysitting me! I just, I...” he started gasping for air, choking on his sobs.

“No, don’t be sorry, you’re not a burden!” he hugged his brother and rubbed circles on his back. “Shh, shh, you’re okay. No tears okay? Just deep breaths, breathe with me.” He did a few deep breaths, Ciel tried to follow. He calmed down and his breathing evened out. “Better?” Ciel nodded. “You can’t work yourself up like that, especially in the middle of a crisis. It’ll just make you sicker.”

“I know, I’m just over thinking…and in pain,” he admitted, “especially in my legs and back.”

“Do you want me to run you a bath? The heat might help,” he suggested. Ciel nodded. “Okay, I’ll get it set.” He helped Ciel up. Ciel winced when he put any weight on his legs. They walked to the bathroom together, Ciel sat on the edge of the tub as Vincent started the bath. “Let me see your legs.” Ciel slipped his flannel bottoms down and kicked them off. Vincent grabbed one foot and turned the leg examining it. It looked a little swollen and red but not too bad. He grabbed the other and saw some small ulcers forming on his ankle. “We need to have Sullivan look at that.” Ciel agreed. Vincent left the bathroom to give Ciel his privacy; he shut the door behind him. At that moment the door to the hallway opened up, Sebastian stood in the door way. He was just about to say something when Vincent motioned him to be quiet and step back out in the hallway. He shut the door and turned to Sebastian, anger burning in his eyes. “Where were you?”

“On the mission,” Sebastian sighed. His hair messy from pulling at it, his eyes swollen from crying, and his shoulders hung like he held the weight of the world on them.

“This whole time?” Vincent stomped his foot. “It doesn’t take that long to chop off a few heads, destroy a few brains!” Sebastian flinched at his words, guilt bubbling up. “It’s been days! You said two days tops and…” he looked around the hallway noticing it was eerily empty. “Where’s dad?” Sebastian looked away as he reached into his pocket. He couldn’t look at those eyes, so similar to the ones he watched life drain out of not long ago. “No,” Vincent shook his head in disbelieve. “No…”

“I’m sorry,” Sebastian handed him the ring. He placed his other hand on Vincent’s shoulder. “I’m so sor…” Vincent punched him as hard as he could in the jaw.

“You’re sorry? What did you do? Where were you when he needed you?” he landed a few more punches to his chest. “Why didn’t you protect him? He would have risked everything to protect you!” Sebastian let him throw as many punches as he wanted, as he needed. He knew the pain all too well. After a while Vincent stopped, breathing ragged he fell back against the wall and let it support his weight.

“I tried, there were more than we originally thought,” Sebastian’s voice was hollow. “I did as your father asked.” Vincent nodded. Part of him knew it really wasn’t Sebastian’s fault.

“We can’t tell Ciel.”  

“What do you mean? Of course we have to tell him!”

“Not right now!” his temper flared back up. “While you were away he went into a crisis!”

“Is he okay?” Sebastian went pale. He hated leaving Ciel for long periods of time, even if he was with his twin.

“He’s fine now. He’s in a lot of pain but I have him soaking in the tub,” he sighed. Relief washed over Sebastian. “He needs more meds though, we need to see Sullivan.”

“Okay, I’ll help you pack up and I’ll get us there right away,” he went for the door but Vincent blocked him.

“I just calmed him down, please don’t go in there,” his eyes threatened to spill tears. “If he sees you without dad…I can’t tell him yet.”

“What can I do?” he backed away.

“Wait in the car. I’ll get you when he falls asleep. We can start driving to Sullivan’s then.” Sebastian nodded. “I want to make sure she’s there when we tell him, just in case it goes bad.” Sebastian agreed and waited in the car. Ciel was finally relaxed enough from the bath, though still in pain. He fell asleep a few minutes after his head hit the pillow. Vincent silently packed everything up and brought it out to the car. Sebastian carefully picked up Ciel. Ciel snuggled into his warmth but stayed asleep. When they got to the car they buckled Ciel in, and then covered him with multiple blankets. They sat in silence the whole drive, not wanting to wake up Ciel and not wanting to discuss the recent death. 

*

They drove up the dirt path to their mansion in the middle of the forest. It was inherited by the Phantomhives. Their friend, Sieglinde Sullivan, rarely left the residence. They left it in her care when they were on the road. It was heavily veiled by trees and warded against supernatural beings, except Sebastian. When they got out of the vehicle they were relieved to see Ciel still slumbering. Sebastian carried him while Vincent grabbed their bags. Vincent only raised his hand to knock when the door opened. Sieglinde cocked her head and looked them over.

“Don’t look so shocked. Did you really think I couldn’t detect your presences?” she moved to the side so they could enter. “Whoa, those are some dark auras! Even for you,” she nodded to Sebastian. She regarded the three of them. “It’s Vincent, isn’t it?” They nodded. Sebastian carried Ciel to his room and tucked him into his bed. He silently closed the door and went back to the others.

“It was a massive outbreak,” Sebastian started. “The recently dead reanimated and infected others. Then long dead corpses dug their way out as well.”

“Whoa, like been in the ground for years dead?” she questioned.

“Seb, you never mentioned that,” Vincent faltered.

“You never asked,” Sebastian shrugged. “He thought he could beat them, told me to take everyone to safety. I don’t know how he held up as well as he did honestly.”

“I’m sorry Seb. I shouldn’t have blamed you.”

“Guys, this is not good,” she stammered. “This really isn’t good.”

“Have you dealt with the undead like that before?”

“Not in my hundreds of years,” she bit her lip. “This is new. Someone is doing this, someone very powerful.”

“Great, just what we need,” Sebastian sighed and sat down in one of the chairs.

“But you scheduled a blast to that town right? The other hunters will deal with it.” Vincent tried.

“That might take care of the undead, but not who’s controlling them,” Sieglinde answered. She pulled out an ancient book and waved it in front of them. “I’ll see what I can find in here. That’s not the only reason you’re here though is it?”

“Ciel had another crisis, he says he’s okay but I can tell he’s in a lot of pain.”

“He needs more medicine doesn’t he?” she mused. “That poor boy.”

“Isn’t there anything else you can do?” Sebastian snapped. “Why can’t you just cure him?”

“I’m doing what I can!” she snapped back. “I practice medicine and witch craft, I don’t perform miracles,” she lifted her skirt to show her two prosthetic legs made out of wood. Both had various symbols and spells carved into them. “If I could, don’t you think I’d do something about this!” Sebastian looked ashamed at himself, his face softened.

“I’m sorry, I didn’t mean…”

“No, I’m sorry too. You’ve all been through a lot this week. It’s been years and I’m still bitter, I should get over it by now,” she sighed.

“We haven’t told him yet,” Vincent added quietly. “He doesn’t know about dad.”

“You’re worried he’ll get worse?” Both men nodded. “I’ll cast a healing spell. I can’t reshape cells, but maybe I can help with his pain.”

“He has some sores on one of his legs too.”

“Okay,” she smiled sadly. “At least I can heal that,” she went to her potions room and left the men alone. They looked at each other, unsure of what to say.

“I forget he was like a dad to you too,” Vincent rubbed the back of his neck. “Especially considering your real father,” he held back tears. “Did h-he…”

“He didn’t suffer,” he reassured. Vincent let out a deep sigh. “He didn’t turn either.”

“Good, he wouldn’t have wanted that,” he swallowed. “Have you remembered anything new?”

“No, unfortunately I haven’t. Do you think my dad could be tied to this, whatever the hell happened?”

“Who knows? My dad believed he found you for a reason. What if this is it? Maybe you’re supposed to help us fight whatever caused the outbreak.”

“Maybe,” he thought back to the day he was found.

***

He woke up in a dark room lying on the floor. His head was pounding and he had something heavy pinning him down. He didn’t know where he was. The more he thought, he realized he didn’t even know who he was. Bright light flooded the room, blinding him.

“Looks like we were too late,” called a rough man’s voice. “She’s long dead.”

“Why would you get a vision like that just for us to be too late?” a softer voice answered.

“Well we were supposed to save her, we messed up,” he growled.

“When have we ever been too late? Never! Maybe we’re supposed to save him!” His eyes began to adjust. He saw two men, both thin and tall. One had long silver hair in a ponytail, his face and arms covered in scars, dressed head to toe in black. The other had short jet black hair and a kind face. He crouched down to his level and extended a black gloved hand out. “Hey, are you okay?”

“Vincent, move out of the way! Let me just kill this thing and get it over with!”

“Father!” he turned and snapped at the long hair man. “He’s just a child!”

“He’s a demon! Look at his eyes!” he shuffled over. He lifted up the dead woman’s body that was pinning the boy to the floor and tossed her aside. He pulled out a knife and pointed towards the boy. The boy trembled scared and confused.

“Don’t you touch him!” the younger man put himself between the two. “He’s innocent!”

“Listen, every demon starts as a child! Once they get older and start killing people we hunt them. Either way they all end up dead. If we take him out now, we won’t worry about him later on.”

“No!” he picked up the child and held him on his hip like he was a toddler. “We were sent here for a reason! I believe the reason is him! That woman’s been dead far too long for us to have ever had a chance to save her! Besides, do you really think he did all of that?” He cocked his head towards the bloody corpse. She had huge chunks of flesh taken out at various places. The other man sighed and put his knife away.

“Fine, have it your way. If that thing lays a hand on my grandchildren though…”

“He won’t,” Vincent promised. “I would never put my sons in harm’s way. I might not have visions but I have my gut instinct.” The older one grumbled and walked past them to examine the scene. “Sorry about Cedric, he’s just a bitter old man.” Vincent saw the boy trying to look at the woman’s corpse so he covered the boy’s eyes. “You don’t need to see that,” he whispered softly. “Did you live here? What happened?”

“I don’t know. I don’t remember anything,” he started to cry. “My head hurts!”

“Hey, don’t cry,” he gently rocked the boy. He was use to calming down his own children. He only looked after them for a year now, but he was a natural. “Do you know your name?” The boy shook his head no. “It’ll be okay, I’ll take care of you.”

The drive back to the house was tense. The older man, Cedric, kept making remarks on what his grandchildren would think of the new addition to the family or worse what could happen if the boys all fought. When they got to the door they were greeted by two young boys that were nearly identical. One was smaller, thinner, and paler. They both had the same sparkling blue eyes their dad had.

“Who’s this daddy?” the smaller one asked.

“A monster,” grumbled Cedric. Both boys looked frightened.

“No,” Vincent corrected. “A friend,” he set the boy down. He seemed to be only a few years older than the twins and just slightly taller. “This is Ciel and this is Vincent Jr.”

“He looks like a lost puppy,” the bigger twin, Vincent Jr., observed. “He’s not going to live with us is he?” he pouted.

“I like puppies,” the smaller one, Ciel, smiled ignoring his brother’s sour mood. “We had one when we lived with mom, his name was Sebastian. He kept us safe when mom was at work. He was even specially trained for me! He knew how to get me water bottles, and he reminded me to take my medication, and if I wasn’t feeling good he’d get help,” he rambled on as he fondly reminisced about his dog.

“He wasn’t a puppy Ciel, he was a big dog,” the other twin rolled his eyes. “He weighed more than you even!”

“So? All dogs are puppies!” he countered.

“Boys!” they both stopped arguing and looked at their father. “Yes he’s staying with us,” one twin smiled and the other frowned. “He doesn’t have any family, so we’re going to be his family.”

“He’s not mine!” the pouty boy stomped his feet. “I already have a brother! I don’t need a fake one!”

“He’s all alone?” Ciel hugged the unnamed boy. “I’ll make sure you’re never alone again. Welcome home! What’s your name?”

“He doesn’t remember, he lost all his memories,” Vincent explained. Ciel nodded.

“I’m sorry you don’t remember, but we can make new memories.” The boy started feeling better. At least one of the twins liked him.

“Sebastian is a nice name,” the boy finally mumbled shyly. “Can I use it?” he was hugged even tighter.

“I like that!”

“You want to have a dog’s name?” the other laughed. “That’s weird,” he walked off to join his grandpa, who was sitting on a couch, still complaining and chugging a beer.

“Vince is always grumpy,” he finally let Sebastian go. “I’m not though!”

“Sebastian?” Vincent got his attention. “I like that name too,” he smiled warmly. “Now that you’re family, you need to know something important about Ciel. Ciel, well he’s sick.”

“He’s sick?” Sebastian glanced back at the smiling boy. “What’s wrong with him? He’ll get better right?”

“No,” Vincent frowned. “He won’t get any better. It’s something he was born with.”

“But…” his lip started to tremble. “He’s so nice, like you.”

“It’s okay. We give him medicine and a lot of the time he’s fine. But if he says he doesn’t feel good you tell me right away, he can get very sick, very fast,” Vincent ruffled Ciel’s hair. “We’ll go over it more a different day. Just for now, keep an eye on him okay?”

“Okay,” Sebastian nodded. “I’ll protect him!” They all smiled.

“You better keep that thing locked up!” Cedric yelled across the room. Ciel and Sebastian looked at Vincent with wide eyes.

“I’m sorry, but he’s right,” Vincent sighed. “Until we know more about you I have to put you in a safe room.”

“Why? He’s family now!” Ciel pouted.

“He’s…different,” he scratched the back of his head. “It’s for everyone’s safety, including his.”

“He’s a fucking demon Vincent just say it!” Cedric slurred.

“Dad!”

“Are you really a demon?” Ciel tilted his head and examined Sebastian. Besides his red eyes he looked like any other human child. “You don’t look like one.”

“I don’t know,” he shrugged. “The old man keeps calling me one.”

“He is a demon,” Vincent confirmed. “But that doesn’t mean he’s bad.” Ciel nodded and hugged his new friend before running off to join his brother. Vincent picked up Sebastian and carried him to the safe room. It was fully furnished with comfy king sized bed. He sat him down on it and smiled. “Don’t let Cedric get to you, he’s…”

“Mean,” Sebastian guessed. Vincent laughed.

“Once you get to know him, he isn’t. He’s just overly cautious,” he kissed the top of his head and hugged him. “Don’t worry, you’re safe here. Try to get some sleep, tomorrow will be a big day.” He walked out and locked the big metal door behind him.

The next day Sebastian met Sieglinde, she drew some blood and ran various tests on both Sebastian and the evidence Cedric collected from the woman’s body.

“Well, we have a match!” she perked up after spending hours in her study. “The woman you found was this little one’s mom,” she nodded towards Sebastian, “and she was definitely human.” Vincent and Cedric blanched. Cedric grabbed a scrap of paper and began frantically drawing on it like he could forget the symbol at any second. He shoved the paper at her.

“This was next to the woman, what does it mean?” he spat out. Her eyes widened.

“This is a demon vanishing spell if I’ve ever seen one! Powerful one at that, whatever she was trying to get rid of must have been blasted back to hell, deep in hell at that.” They all turned to look at Sebastian.

“Do you remember anything?” Vincent tried. “Your mom? Your dad?” Sebastian shook his head.

“I feel something when I try to think of my mom,” he tried focusing. “I feel protected and warm but I can’t even remember what she looked like,” he pouted. “I don’t feel anything when I think about my dad. I’m sorry, I just can’t remember.”

“Are you thinking what I’m thinking?” Vincent asked.

“Daddy came to collect and mommy wasn’t going to let that happen,” Cedric nodded. “You were right, we need to protect him.” Cedric kneeled down next to Sebastian. “Son, I’m sorry I called you a monster. Can you forgive me?”

“But am I really a monster?”

“No,” Cedric smiled. “You might be part demon, but you’re also human. I was mistaken.”

“Do I have to stay in that little room? I don’t like it in there by myself.”

“No, you don’t ever have to be locked up again.” Sebastian smiled. “We’ll figure this out, don’t worry.” From that day Cedric and Vincent treated Sebastian as if he really was family. Cedric never called him monster or demon again. They spent countless hours researching anything they could to try to find out more on Sebastian’s father. Sieglinde tried various memory recalling techniques to try to help Sebastian remember something. Everything kept coming up blank. Before Sebastian they never even knew humans and demons could have children together. They dug through countless documents and ancient texts, only to find no one like Sebastian to ever be recorded. They were in this adventure alone without a paddle, and they were drowning.


End file.
